<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var app=10;
        var App=100;
        console.log(app);
        console.log(App);
        //不能用数字开头命名,变量名应该有意义
        //name 不要使用 尽量不要使用name做为变量名
        
    </script>
</body>
</html>